Direct Deposition of (BixSb1-x)2Te3 Nanosheets on Si/SiO2 Substrates by Chemical Vapor Transport

The tellurides of bismuth and antimony (Bi2Te3 and Sb2Te3) are prominent members of the V2VI3 material family that exhibit promising topological properties. We provide a method for the rational synthesis of mixed crystals of these materials ((BixSb1-x)(2)Te-3 with x = 0.1,..., 0.9) by means of a bottom-up chemical vapor transport (CVT) approach. Thermodynamic calculations showed the synthesis to be possible in the temperature range of 390-560 degrees C without significant enrichment of either component and without adding a transport agent. The starting materials were synthesized and verified by X-ray diffraction (XRD). Optimization experiments showed the ideal conditions for nanosheet synthesis to be T-2 = 560 degrees C, T-1 = 390 degrees C with a reaction time of t = 36 h. Crystals with heights of down to 12 nm (12 quintuple layers) were syntheszed and analyzed by means of scanning electron microscopy, energy-dispersive X-ray spectrometry, and atomic force microscopy. High-resolution transmission electron microscopy confirmed the R (3) over barm crystal structure, high crystallinity, and overall quality of the synthesized (BixSb1-x)(2)Te-3 nanosheets. Magnetotransport measurements revealed that such ternary compounds can have a significantly reduced carrier density compared to the binary parent compounds.